"Meet Alexis Olympia Ohanian Jr," Williams wrote alongside the photo of herself and her daughter. "You have to check out link in bio for her amazing journey. Also check out my IG stories."

The video, posted to Williams' website, is called "Hello World." It documents Williams' pregnancy journey from the start — literally the moment when the doctor said, "Okay, so you're pregnant" — to the moment the tennis star left the hospital with her baby, covering all the moments in between, like attending baby class and glamming up for the Met Ball.

The baby, as per the video, was born September 1, and weighed six pounds, fourteen ounces. (The video cheekily adds that the child already has one Grand Slam under her belt. Pretty big deal for a brand new human.) The baby is named after her father, Reddit co-founder Alexis Ohanian, so she's officially a "junior." Williams shares in the video that she experienced complications with the pregnancy, although she doesn't specify what happened.

"We're leaving the hospital after six — six [or] seven days," Williams says in the video, holding baby Alexis.

"We did it, baby," Ohanian, off-camera, adds.

"It's been a long time, but we had a lot of complications, but look who we got! We got a baby girl," Williams says.